Preparing honestly
How do you prepare for the TechFirst technical aptitude assessment?
Broadly, because nobody outside the scheme knows its content yet. GOV.UK says further information will be available soon. The honest preparation is fluency in the ideas any technical aptitude test is likely to touch: number bases, logic, simple cryptography, networks and counting. The worked example and warm-ups below are ours.
Our worked example: why length beats variety. A password of 8 lowercase letters has 268 = 208,827,064,576 possibilities. Allowing upper case and digits as well (62 symbols) gives 628 = 218,340,105,584,896, about a thousand times more. But simply using 12 lowercase letters gives 2612 = 95,428,956,661,682,176, over four hundred times more than the 8-character mixed password.
The reasoning, not the numbers
Each extra character multiplies the possibilities by the size of the alphabet, so length grows the search space exponentially. Adding symbol types only enlarges the base. Four more lowercase letters multiply by 264 = 456,976; changing 26 symbols to 62 multiplies by (62/26)8, which is only about 1,046.
That is the kind of step an aptitude assessment rewards: turning a vague idea, "stronger password", into a count that can be compared.
What this does not mean
Real attackers rarely try every combination; they try common words and leaked passwords first, so a long password made of predictable words can still fall quickly. Counting shows the ceiling, not the whole story.
Saying that out loud in an interview, that a model has limits, is worth as much as the arithmetic.
Six warm-up questions of our own, with answers| # | Our question | Answer |
|---|
| 1 | Convert the binary number 101101 to decimal. | 45: 32 + 8 + 4 + 1 |
| 2 | Encrypt CODE with a Caesar shift of 3. | FRGH |
| 3 | For which inputs does A XOR B give 1? | Exactly when A and B differ: 0,1 or 1,0 |
| 4 | How many addresses are in an IPv4 /24 block? | 256, since 32 − 24 = 8 bits gives 28 |
| 5 | What is the ASCII code of the capital letter A? | 65 |
| 6 | With even parity, what bit is added to 1011001? | 0, since the data already has four 1s |
The worked example and warm-ups are ours, written on 31 October 2026, and are not items from any TechFirst, CyberFirst or NCSC assessment, whose content has not been published. The NCSC's Empower Cyber Week packs on binary, logic gates and ASCII are free on its Key stage 3 resources page.
